1. Field of the Invention
The present invention relates to a wireless communication system. More particularly, the present invention relates to a method and an apparatus for processing multiple Frequency Assignment (FA) configuration information to support an overlay mode.
2. Description of the Related Art
As wireless communication systems advance, types of services and an amount of traffic provided by the wireless communication systems are increasing. To meet those demands, various wireless communication technologies are suggested. Among them, an Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA) scheme is under development as the most prominent next-generation wireless communication technique. A Wireless Metropolitan Area Network (WMAN) of the Institute of Electrical and Electronics Engineers (IEEE) standard 802.16 is also adopting the OFDM or OFDMA as its standard.
Meanwhile, since frequency resources are limited in the wireless communication systems, available frequency bands are also restricted. By modifying the standard, the wireless communication systems are evolving to provide a higher data rate than the existing systems and to address implementation issues. In a course of the evolution, various systems can coexist in the same area according to their compatibility with the existing systems.
FIG. 1 is a diagram of a structure supporting a single frequency band and a structure supporting two frequency bands in a wireless communication system according to the related art.
In the wireless communication system, in particular, in a broadband wireless communication system represented by the IEEE standard 802.16, a Base Station (BS) operates using one Frequency Assignment (FA) or two or more FAs. The BS offers a radio channel to a Mobile Station (MS) through its FA.
Referring FIG. 1, an MS 100 can move from a FA1 region 120 to a FA2 region 140, which is referred to as a handover between the FAs. Herein, the FA1 region 120 indicates a service coverage area where the MS 100 receives a wireless communication service using the FA1, and the FA2 region 140 indicates a service coverage area where the MS 100 receives the wireless communication service using the FA2. When the MS 100 traveling in the FA1 region 120 can operate in only one FA or the FA1 and the FA2 are provided by different BSs, the MS 100 hands over between the FAs and then receives the radio channel using the FA2.
For high data rate transmission, when an MS 150 operates in two or more FAs or the two or more FAs are provided by a single BS, the MS 150 can use the radio channel through all of the FA1 region 160 and the FA2 region through the FA_n 180. As such, the MS and the BS can transmit and receive large amounts of data at a high data rate by using the plurality of the FA_1 through the FA_n. Hereinafter, the technique for using the existing multiple FAs without allocating a new frequency band is referred to as a frequency overlay. In the wireless communication system, it is necessary to share information (e.g., a center frequency of the FA, a bandwidth of the FA, and an offset of the FA) relating to every FA supporting the frequency overlay.
Thus, a need exists for a method and apparatus for efficiently processing configuration information of the multiple FAs supporting the frequency overlay in the wireless communication system.